powerpc: add interrupt_cond_local_irq_enable helper

Simple helper for synchronous interrupt handlers (i.e., process-context)
to enable interrupts if it was taken in an interrupts-enabled context.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-30-npiggin@gmail.com

arch/powerpc/include/asm/interrupt.h

@@ -3,6 +3,7 @@
 #define _ASM_POWERPC_INTERRUPT_H
 
 #include <linux/context_tracking.h>
+#include <linux/hardirq.h>
 #include <asm/ftrace.h>
 
 struct interrupt_state {
@@ -298,4 +299,10 @@ DECLARE_INTERRUPT_HANDLER_ASYNC(TAUException);
 void replay_system_reset(void);
 void replay_soft_interrupts(void);
 
+static inline void interrupt_cond_local_irq_enable(struct pt_regs *regs)
+{
+	if (!arch_irq_disabled_regs(regs))
+		local_irq_enable();
+}
+
 #endif /* _ASM_POWERPC_INTERRUPT_H */

arch/powerpc/kernel/traps.c

@@ -343,8 +343,8 @@ static bool exception_common(int signr, struct pt_regs *regs, int code,
 
 	show_signal_msg(signr, regs, code, addr);
 
-	if (arch_irqs_disabled() && !arch_irq_disabled_regs(regs))
-		local_irq_enable();
+	if (arch_irqs_disabled())
+		interrupt_cond_local_irq_enable(regs);
 
 	current->thread.trap_nr = code;
 
@@ -1555,9 +1555,7 @@ static void do_program_check(struct pt_regs *regs)
 	if (!user_mode(regs))
 		goto sigill;
 
-	/* We restore the interrupt state now */
-	if (!arch_irq_disabled_regs(regs))
-		local_irq_enable();
+	interrupt_cond_local_irq_enable(regs);
 
 	/* (reason & REASON_ILLEGAL) would be the obvious thing here,
 	 * but there seems to be a hardware bug on the 405GP (RevD)
@@ -1622,9 +1620,7 @@ DEFINE_INTERRUPT_HANDLER(alignment_exception)
 	int sig, code, fixed = 0;
 	unsigned long  reason;
 
-	/* We restore the interrupt state now */
-	if (!arch_irq_disabled_regs(regs))
-		local_irq_enable();
+	interrupt_cond_local_irq_enable(regs);
 
 	reason = get_reason(regs);
 
@@ -1785,9 +1781,7 @@ DEFINE_INTERRUPT_HANDLER(facility_unavailable_exception)
 		die("Unexpected facility unavailable exception", regs, SIGABRT);
 	}
 
-	/* We restore the interrupt state now */
-	if (!arch_irq_disabled_regs(regs))
-		local_irq_enable();
+	interrupt_cond_local_irq_enable(regs);
 
 	if (status == FSCR_DSCR_LG) {
 		/*
@@ -2172,9 +2166,7 @@ DEFINE_INTERRUPT_HANDLER(SPEFloatingPointException)
 	int code = FPE_FLTUNK;
 	int err;
 
-	/* We restore the interrupt state now */
-	if (!arch_irq_disabled_regs(regs))
-		local_irq_enable();
+	interrupt_cond_local_irq_enable(regs);
 
 	flush_spe_to_thread(current);
 
@@ -2221,9 +2213,7 @@ DEFINE_INTERRUPT_HANDLER(SPEFloatingPointRoundException)
 	extern int speround_handler(struct pt_regs *regs);
 	int err;
 
-	/* We restore the interrupt state now */
-	if (!arch_irq_disabled_regs(regs))
-		local_irq_enable();
+	interrupt_cond_local_irq_enable(regs);
 
 	preempt_disable();
 	if (regs->msr & MSR_SPE)

arch/powerpc/mm/fault.c

@@ -434,9 +434,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
 		return bad_area_nosemaphore(regs, address);
 	}
 
-	/* We restore the interrupt state now */
-	if (!arch_irq_disabled_regs(regs))
-		local_irq_enable();
+	interrupt_cond_local_irq_enable(regs);
 
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);